block: remove REQ_NOWAIT_INLINE

We had a few issues with this code, and there's still a problem around
how we deal with error handling for chained/split bios. For now, just
revert the code and we'll try again with a thoroug solution. This
reverts commits:

e15c2ffa1091 ("block: fix O_DIRECT error handling for bio fragments")
0eb6ddfb865c ("block: Fix __blkdev_direct_IO() for bio fragments")
6a43074e2f46 ("block: properly handle IOCB_NOWAIT for async O_DIRECT IO")
893a1c97205a ("blk-mq: allow REQ_NOWAIT to return an error inline")

Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-mq.c b/block/blk-mq.c
index a8e6a58f5f28f042248bac7c9eb01c2bbaefd9a2..0835f4d8d42e7e34c043acc040d8f5406b2e2268 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1958,13 +1958,9 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
        rq = blk_mq_get_request(q, bio, &data);
        if (unlikely(!rq)) {
                rq_qos_cleanup(q, bio);
-
-               cookie = BLK_QC_T_NONE;
-               if (bio->bi_opf & REQ_NOWAIT_INLINE)
-                       cookie = BLK_QC_T_EAGAIN;
-               else if (bio->bi_opf & REQ_NOWAIT)
+               if (bio->bi_opf & REQ_NOWAIT)
                        bio_wouldblock_error(bio);
-               return cookie;
+               return BLK_QC_T_NONE;
        }
 
        trace_block_getrq(q, bio, bio->bi_opf);

diff --git a/fs/block_dev.c b/fs/block_dev.c
index eb657ab9406062cdd23136e66fc265e472523a80..677cb364d33f0e43e65d25349fdcdce651a6ca5e 100644 (file)
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -345,24 +345,15 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages)
        struct bio *bio;
        bool is_poll = (iocb->ki_flags & IOCB_HIPRI) != 0;
        bool is_read = (iov_iter_rw(iter) == READ), is_sync;
-       bool nowait = (iocb->ki_flags & IOCB_NOWAIT) != 0;
        loff_t pos = iocb->ki_pos;
        blk_qc_t qc = BLK_QC_T_NONE;
-       gfp_t gfp;
-       int ret;
+       int ret = 0;
 
        if ((pos | iov_iter_alignment(iter)) &
            (bdev_logical_block_size(bdev) - 1))
                return -EINVAL;
 
-       if (nowait)
-               gfp = GFP_NOWAIT;
-       else
-               gfp = GFP_KERNEL;
-
-       bio = bio_alloc_bioset(gfp, nr_pages, &blkdev_dio_pool);
-       if (!bio)
-               return -EAGAIN;
+       bio = bio_alloc_bioset(GFP_KERNEL, nr_pages, &blkdev_dio_pool);
 
        dio = container_of(bio, struct blkdev_dio, bio);
        dio->is_sync = is_sync = is_sync_kiocb(iocb);
@@ -384,7 +375,6 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages)
        if (!is_poll)
                blk_start_plug(&plug);
 
-       ret = 0;
        for (;;) {
                bio_set_dev(bio, bdev);
                bio->bi_iter.bi_sector = pos >> 9;
@@ -409,14 +399,7 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages)
                        task_io_account_write(bio->bi_iter.bi_size);
                }
 
-               /*
-                * Tell underlying layer to not block for resource shortage.
-                * And if we would have blocked, return error inline instead
-                * of through the bio->bi_end_io() callback.
-                */
-               if (nowait)
-                       bio->bi_opf |= (REQ_NOWAIT | REQ_NOWAIT_INLINE);
-
+               dio->size += bio->bi_iter.bi_size;
                pos += bio->bi_iter.bi_size;
 
                nr_pages = iov_iter_npages(iter, BIO_MAX_PAGES);
@@ -428,13 +411,7 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages)
                                polled = true;
                        }
 
-                       dio->size += bio->bi_iter.bi_size;
                        qc = submit_bio(bio);
-                       if (qc == BLK_QC_T_EAGAIN) {
-                               dio->size -= bio->bi_iter.bi_size;
-                               ret = -EAGAIN;
-                               goto error;
-                       }
 
                        if (polled)
                                WRITE_ONCE(iocb->ki_cookie, qc);
@@ -455,19 +432,8 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages)
                        atomic_inc(&dio->ref);
                }
 
-               dio->size += bio->bi_iter.bi_size;
-               qc = submit_bio(bio);
-               if (qc == BLK_QC_T_EAGAIN) {
-                       dio->size -= bio->bi_iter.bi_size;
-                       ret = -EAGAIN;
-                       goto error;
-               }
-
-               bio = bio_alloc(gfp, nr_pages);
-               if (!bio) {
-                       ret = -EAGAIN;
-                       goto error;
-               }
+               submit_bio(bio);
+               bio = bio_alloc(GFP_KERNEL, nr_pages);
        }
 
        if (!is_poll)
@@ -487,7 +453,6 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages)
        }
        __set_current_state(TASK_RUNNING);
 
-out:
        if (!ret)
                ret = blk_status_to_errno(dio->bio.bi_status);
        if (likely(!ret))
@@ -495,10 +460,6 @@ out:
 
        bio_put(&dio->bio);
        return ret;
-error:
-       if (!is_poll)
-               blk_finish_plug(&plug);
-       goto out;
 }
 
 static ssize_t

diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 1b1fa1557e68aefe5cf5df252485d398b8a38e35..feff3fe4467ec97ce92aa7e6b5b13ef05012bb47 100644 (file)
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -311,7 +311,6 @@ enum req_flag_bits {
        __REQ_RAHEAD,           /* read ahead, can fail anytime */
        __REQ_BACKGROUND,       /* background IO */
        __REQ_NOWAIT,           /* Don't wait if request will block */
-       __REQ_NOWAIT_INLINE,    /* Return would-block error inline */
        /*
         * When a shared kthread needs to issue a bio for a cgroup, doing
         * so synchronously can lead to priority inversions as the kthread
@@ -346,7 +345,6 @@ enum req_flag_bits {
 #define REQ_RAHEAD             (1ULL << __REQ_RAHEAD)
 #define REQ_BACKGROUND         (1ULL << __REQ_BACKGROUND)
 #define REQ_NOWAIT             (1ULL << __REQ_NOWAIT)
-#define REQ_NOWAIT_INLINE      (1ULL << __REQ_NOWAIT_INLINE)
 #define REQ_CGROUP_PUNT                (1ULL << __REQ_CGROUP_PUNT)
 
 #define REQ_NOUNMAP            (1ULL << __REQ_NOUNMAP)
@@ -420,13 +418,12 @@ static inline int op_stat_group(unsigned int op)
 
 typedef unsigned int blk_qc_t;
 #define BLK_QC_T_NONE          -1U
-#define BLK_QC_T_EAGAIN                -2U
 #define BLK_QC_T_SHIFT         16
 #define BLK_QC_T_INTERNAL      (1U << 31)
 
 static inline bool blk_qc_t_valid(blk_qc_t cookie)
 {
-       return cookie != BLK_QC_T_NONE && cookie != BLK_QC_T_EAGAIN;
+       return cookie != BLK_QC_T_NONE;
 }
 
 static inline unsigned int blk_qc_t_to_queue_num(blk_qc_t cookie)